Exploring Speciation

"In chemistry, speciation refers to the distribution of an element amongst chemical species in a system. The five chapters of this book each bring a unique perspective on this type of speciation as it pertains to marine biota, x-ray fluorescence spectroscopy, and other areas of interest. Chapter One investigates the bioaccumulation of cadmium, a toxic heavy metal, in marine biota in the Egyptian coastal zones. Chapter Two scrutinizes the applications of energy and wavelength dispersive spectroscopic techniques in various materials. Chapter Three explains the phenomenon of thermoluminescence and the effect of varying readout heating rates on the dosimetric properties of TLD-100 (LiF: Mg, Ti) irradiated with 6 MV X-ray. Chapter Four focuses on the applications of different X-ray spectroscopy techniques and their use in the elemental analysis of water, coal, fly ash, and fertilizer samples. Finally, Chapter Five describes how to select the best speciation model from studies based on potentiometric measurements"-- Provided by publisher Contents 7 Preface 9 Chapter 1 13 Exploring Cadmium Speciation in the Aquatic Ecosystem: A Case Study 13 Abstract 13 1. Introduction 14 2. Speciation of CD in the Aquatic Environment in Egyptian Coast, Case Study 19 2.1. An Overview of the Metal Pollution in the Marine Environment in Egyptian Coast 19 2.2. Speciation of Cadmium in Aquatic Environment 21 2.2.1. Cadmium in Sediment 21 2.2.1.1. Marine Sediment (Mediterranean and Red Sea) 21 2.2.1.1.1. The Egyptian Coast of the Mediterranean Sea 21 2.2.1.1.2. The Egyptian Coast of the Red Sea 29 2.2.2. Fresh Water Sediment 32 2.2.2.1. Nile River Sediments 32 2.2.2.2. Nile River Branches Sediment 34 2.2.2.3. Nile Lakes Sediments 35 2.2.2.3.1. Nasser Lake 35 2.2.2.3.2. Qarun Lake 37 2.2.3. Brackish Water Sediments (Four Nile Delta Lakes) 39 2.2.3.1. Lake Bardawil (Northern Egypt) 44 2.3. Cadmium in Aquatic Biota 45 2.3.1. Marine Environment 45 2.3.1.1. Fish 45 2.3.1.2. Marine Organisms 51 2.3.1.3. Marine Seaweed 58 2.3.2. Fresh Water Environment 61 2.3.2.1. Fresh Water Fish 61 2.3.2.2. Freshwater Organisms 64 2.3.2.3. Brackish Water Fish (Four Nile Delta Lakes) 68 2.3.2.3.1. Burullus 68 2.3.2.3.2. Edku 70 2.3.2.3.3. Manzalah 71 2.3.2.3.4. Maryout 73 2.3.2.4. The Extent of Cadmium Pollution of Marine Organisms on Egyptian Coasts 73 Conclusion 75 References 78 Biographical Sketch 97 Chapter 2 99 Investigation of Photon Atom Interactions in Various Chemical Materials Employing X-Ray Spectroscopic Techniques 99 Abstract 99 Introduction 100 Photon-Atom Interaction Processes 101 Atomic Inner-Shell Photoionization 104 Inner-Shell Vacancy Decay and Subsequent Processes 106 Non-Radiative Transitions 107 Radiative Transitions 107 Physical Parameters Associated with Inner-Shell Vacancy Decay 109 Mass Attenuation Coefficients 109 Fluorescence, Auger, and Coster-Kronig Yields 111 Vacancy Transfer Probabilities 112 Fractional X-Ray Emission Rates 113 X-Ray Production Cross-Sections 114 Near-Edge Processes Contributing to the Absorption of Incident Photons 115 Resonant Raman Scattering 116 X-Ray Absorption Fine Structure (XAFS) Process 118 Single Scattering 119 Multiple Scattering 120 Elastic Scattering 120 Form Factor Formalism 121 S-Matrix Calculations 124 Inelastic Scattering 125 Compton Scattering from Free Electrons 126 Compton Scattering from Bound Electrons 127 Compton Profile and Relativistic Impulse Approximation 128 Effect of magnetic Field on the X-Ray Line Spectra 129 Application of X-Ray Spectroscopy: A Possible Probe to Examine the Chemical Effect in Distinct Materials 130 Acknowledgments 132 References 133 Chapter 3 141 Effect of Readout Heating Rate and Correction for Temperature Lag, Effective Heating Rate and Thermal Quenching to the Response of TLD-100 (LiF: Mg, Ti) 141 Abstract 141 1. Introduction 142 2. Thermoluminescence Dosimeter Readout System 144 2.1. Sample Detector Housing 146 3. Experimental Details 149 3.1. TLD Measurements Using Photon Beam 149 3.2. TLD Sorting and Calibration 151 3.3. Effect of Heating Rate on TLD-100 153 3.4. The General Order Kinetics (May and Partridge Model) 154 4. Correction for Temperature Lag, Effective Heating Rate and Thermal Quenching 155 4.1. Corrections for the Temperature Lag in TL Glow-Curve Measurements 155 4.2. The Effective Rate of Heating (βeff) 158 4.3. Thermal Quenching 159 5. Results and Discussion 161 6. Summary 174 References 175 Chapter 4 181 X-Ray Fluorescence Spectroscopy: Rapid Tool for the Assessment of Elemental Composition in Various Environmental Samples 181 Abstract 181 Introduction 182 Energy Dispersive X-Ray Fluorescence Spectrometer 183 Excitation Sources 185 X-Ray Tube-Based Excitation Sources 185 Radioisotope-Based Excitation Sources 187 Various Experimental Setups 187 Geometrical Setups 187 EDXRF Experimental Setup 190 WDXRF Experimental Setup 192 Relationship between Fluorescent X-Ray Intensity and Mass of Element in the Target 195 The Self-Absorption Correction Factor (β) 198 Calculations of the Area under the X-Ray Fluorescent Peak 198 The Efficiency of the Detector 200 Evaluation Procedure 200 WDXRF Setup 200 Environmental Applications of XRF Technique 201 Elemental Analysis of Water Samples 201 Elemental Analysis of Coal and Fly Ash Samples 203 Elemental Analysis of Fertilizer Samples 207 Acknowledgments 209 References 209 Chapter 5 215 Speciation: How to Propose Models and Select the Best of Them 215 Abstract 215 Introduction 216 Model Development Approach 221 Selection of the Best Model 227 Conclusion 233 Acknowledgements 234 References 234 Index 241 Blank Page 2 Blank Page 247 35